In an aluminum alloy wheel production process, a coating process is a very important working process, which mainly provides excellent appearance effects and corrosion resistance for wheels. However, primer or colored paint cannot appear on to-be-mounted parts of the wheels generally. In order to achieve this purpose, in current all wheel manufacturing enterprises, flange faces and central holes of the wheels are usually separately protected, and utilized protection devices for the wheels of different sizes are different with each other. Therefore, the efficiency is low and operations are very inconvenient.